Drum is the soul of musical instrument, which directs the rhythm of a melody by means of its drumbeat, and further, the drumbeat can encourage people's spirit. In jazz music, there are several kinds of drums being performed, such as bass drum, snare drum, tambourinem, and tom tom etc., however, the structure of which and the material used are almost the same. For the manufacturing of such kinds of drums, the technique required is to provide a drum with better tonality and timbre and the key point to provide better tonality and timbre is determined by means of the minimum volume of vibration noise while beating. Therefore, in addition to the material used or the single layer of double-layer of drumhead constructed, the measure to affix the drumhead and the angle provided in the affixture are more than important. The present inventor in endeavoring in the improvement of the drumhead structure and one of his invention has been approved in U.S.A. with a Letter U.S. Pat. No. 4,616,552. As shown in the attached FIGS. 1, 2, and 3, the drumhead is completed by means of a central plane radially extending outward to a proper distance from the side frame and turning downward by pressure to form a small curved surface, said small curved surface is then extending horizontally for a proper distance from its terminal edge and then being pressed downward to form a large curved surface, said large curved surface is then arranged to connect with the side frame of the drum. The connection of the large curved surface with the side frame of the drum is as illustrated in FIGS. 2 and 3 wherein said side frame is composed of an internal aluminum rod and an external aluminum channel and the terminal edge of the drumhead is encircled between said external aluminum channel and said internal aluminum rod. Although some improvement has been achieved, this arrangement of the drumhead is still not satisfactory and there is still problems pending unsettled: (1) the drumhead is easy to get loosened and dropped while beating due to heavy vibration and the displacement of the aluminum rod against aluminum channel; (2) the loosening of the drumhead due to bad connection with the side frame, the tonality and timbre are greatly interfered while beating.
In view of the said problems, the present inventor has finally created the present invention to provide a better structure to connect the drumhead and the side frame by means of a tetoron cloth drumhead thus encircled around the aluminum rod and aluminum channel is then extending for a distance to form a curved surface as an outer layer of drumhead to strengthen its connection with the drum so as to prevent any loosing problem during beating. Another object of the present invention is to provide a better tonality and timbre of drumbeat by means of the arrangement of the double-layer curved surface.